Part 10 (1/2)

There is only one continuous statistical record of the abundance of animals, that is the returns of the fur trade. These have been kept for over 200 years, and if we begin after the whole continent was covered by fur-traders, they are an accurate gauge of the abundance of each species. Obviously, this must be so, for the whole country is trapped over every year, all the furs are marketed, most of them through the Hudson's Bay Company, and whatever falls into other hands is about the same percentage each year, therefore the H. B. Co. returns are an accurate gauge of the relative rise and fall of the population.

Through the courtesy of its officials I have secured the Company's returns for the 85 years--1821-1905 inclusive. I take 1821 as the starting-point, as that was the first year when the whole region was covered by the Hudson's Bay Company to the exclusion of all important rivals.

First, I have given these accounts graphic tabulation, and at once many interesting facts are presented to the eye. The Rabbit line prior to 1845 is not reliable. Its subsequent close coincidence with that of Lynx, Marten, Skunk, and Fox is evidently cause and effect.

The Mink coincides fairly well with Skunk and Marten.

The Muskrat's variation probably has relation chiefly to the amount of water, which, as is well known, is cyclic in the north-West.

The general resemblance of Beaver and Otter lines may not mean anything. If, as said, the Otter occasionally preys on the Beaver, these lines should in some degree correspond.

The Wolf line does not manifest any special relations.h.i.+p and seems to be in a cla.s.s by itself. The great destruction from 1840 to 1870 was probably due to strychnine, newly introduced about then.

The Bear, Badger, and Wolverine go along with little variation.

Probably the c.o.o.n does the same; the enormous rise in 1867 from an average of 3,500 per annum. to 24,000 was most likely a result of accidental acc.u.mulation and not representative of any special abundance. Finally, each and every line manifests extraordinary variability in the '30's. It is not to be supposed that the population fluctuated so enormously from one year to another, but rather that the facilities for export were irregular.

The case is further complicated by the fact that some of the totals represent part of this year and part of last; nevertheless, upon the whole, the following general principles are deducible:

(a) The high points for each species are with fair regularity 10 years apart.

(b) In the different species these are not exactly coincident.

(c) To explain the variations we must seek not the reason for the increase--that is normal--but for the destructive agency that ended the increase.

This is different in three different groups.

First. The group whose food and enemies fluctuate but little. The only examples of this on our list are the Muskrat and Beaver, more especially the Muskrat. Its destruction seems to be due to a sudden great rise of the water after the ice has formed, so that the Rats are drowned; or to a dry season followed by severe frost, freezing most ponds to the bottom, so that the Rats are imprisoned and starve to death, or are forced out to cross the country in winter, and so are brought within the power of innumerable enemies.

How tremendously this operates may be judged by these facts. In 1900 along the Mackenzie I was a.s.sured one could shoot 20 Muskrats in an hour after sundown. Next winter the flood followed the frost and the Rats seemed to have been wiped out. In 1907 1 spent 6 months outdoors in the region and saw only 17 Muskrats the whole time; in 1901 the H. B. Co. exported over 11 millions; in 1907, 407,472. The fact that they totalled as high was due, no doubt, to their abundance in eastern regions not affected by the disaster.

Second. The group that increases till epidemic disease attacks their excessively multiplied hordes. The Snowshoe-Rabbit is the only well-known case today, but there is reason for the belief that once the Beaver were subjected to a similar process. Concerning the Mice and Lemmings, I have not complete data, but they are believed to multiply and suffer in the same, way.

Third. The purely carnivorous, whose existence is dependent on the Rabbits. This includes chiefly the Lynx and Fox, but in less degree all the small carnivores.

In some cases such as the Marten, over-feeding seems as inimical to multiplication as under-feeding, and it will be seen that each year of great increase for this species coincided with a medium year for Rabbits.

But the fundamental and phenomenal case is that of the Rabbits themselves. And in solving this we are confronted by the generally attested facts that when on the increase they have two or three broods each season and 8 to 10 in a brood; when they are decreasing they have but one brood and only 2 or 3 in that. This points to some obscure agency at work; whether it refers simply to the physical vigour of the fact, or to some uncomprehended magnetic or heliological cycle, is utterly unknown.

The practical consideration for the collecting naturalist is this: Beaver, Muskrat, Otter, Fisher, Racc.o.o.n, Badger, Wolverine, Wolf, Marten, Fox reached the low ebb in 1904-5. All are on the upgrade; presumably the same applies to the small rodents. Their decacycle will be complete in 1914-15, so that 1910-11 should be the years selected by the next collecting naturalist who would visit the north.

For those who will enter before that there is a reasonable prospect of all these species in fair numbers, except perhaps the Lynx and the Caribou. Evidently the former must be near minimum now (1909) and the latter would be scarce, if it is subject to the rule of the decacycle, though it is not at all proven that such is the case.

CHAPTER XVI

THE PELICAN TRIP

We were still held back by the dilatory ways of our Indian friends, so to lose no time Preble and I determined to investigate a Pelican rookery.